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1/*
2 * linux/fs/ext4/acl.c
3 *
4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
5 */
6
7#include "ext4_jbd2.h"
8#include "ext4.h"
9#include "xattr.h"
10#include "acl.h"
11
12/*
13 * Convert from filesystem to in-memory representation.
14 */
15static struct posix_acl *
16ext4_acl_from_disk(const void *value, size_t size)
17{
18 const char *end = (char *)value + size;
19 int n, count;
20 struct posix_acl *acl;
21
22 if (!value)
23 return NULL;
24 if (size < sizeof(ext4_acl_header))
25 return ERR_PTR(-EINVAL);
26 if (((ext4_acl_header *)value)->a_version !=
27 cpu_to_le32(EXT4_ACL_VERSION))
28 return ERR_PTR(-EINVAL);
29 value = (char *)value + sizeof(ext4_acl_header);
30 count = ext4_acl_count(size);
31 if (count < 0)
32 return ERR_PTR(-EINVAL);
33 if (count == 0)
34 return NULL;
35 acl = posix_acl_alloc(count, GFP_NOFS);
36 if (!acl)
37 return ERR_PTR(-ENOMEM);
38 for (n = 0; n < count; n++) {
39 ext4_acl_entry *entry =
40 (ext4_acl_entry *)value;
41 if ((char *)value + sizeof(ext4_acl_entry_short) > end)
42 goto fail;
43 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
44 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
45
46 switch (acl->a_entries[n].e_tag) {
47 case ACL_USER_OBJ:
48 case ACL_GROUP_OBJ:
49 case ACL_MASK:
50 case ACL_OTHER:
51 value = (char *)value +
52 sizeof(ext4_acl_entry_short);
53 break;
54
55 case ACL_USER:
56 value = (char *)value + sizeof(ext4_acl_entry);
57 if ((char *)value > end)
58 goto fail;
59 acl->a_entries[n].e_uid =
60 make_kuid(&init_user_ns,
61 le32_to_cpu(entry->e_id));
62 break;
63 case ACL_GROUP:
64 value = (char *)value + sizeof(ext4_acl_entry);
65 if ((char *)value > end)
66 goto fail;
67 acl->a_entries[n].e_gid =
68 make_kgid(&init_user_ns,
69 le32_to_cpu(entry->e_id));
70 break;
71
72 default:
73 goto fail;
74 }
75 }
76 if (value != end)
77 goto fail;
78 return acl;
79
80fail:
81 posix_acl_release(acl);
82 return ERR_PTR(-EINVAL);
83}
84
85/*
86 * Convert from in-memory to filesystem representation.
87 */
88static void *
89ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
90{
91 ext4_acl_header *ext_acl;
92 char *e;
93 size_t n;
94
95 *size = ext4_acl_size(acl->a_count);
96 ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
97 sizeof(ext4_acl_entry), GFP_NOFS);
98 if (!ext_acl)
99 return ERR_PTR(-ENOMEM);
100 ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
101 e = (char *)ext_acl + sizeof(ext4_acl_header);
102 for (n = 0; n < acl->a_count; n++) {
103 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
104 ext4_acl_entry *entry = (ext4_acl_entry *)e;
105 entry->e_tag = cpu_to_le16(acl_e->e_tag);
106 entry->e_perm = cpu_to_le16(acl_e->e_perm);
107 switch (acl_e->e_tag) {
108 case ACL_USER:
109 entry->e_id = cpu_to_le32(
110 from_kuid(&init_user_ns, acl_e->e_uid));
111 e += sizeof(ext4_acl_entry);
112 break;
113 case ACL_GROUP:
114 entry->e_id = cpu_to_le32(
115 from_kgid(&init_user_ns, acl_e->e_gid));
116 e += sizeof(ext4_acl_entry);
117 break;
118
119 case ACL_USER_OBJ:
120 case ACL_GROUP_OBJ:
121 case ACL_MASK:
122 case ACL_OTHER:
123 e += sizeof(ext4_acl_entry_short);
124 break;
125
126 default:
127 goto fail;
128 }
129 }
130 return (char *)ext_acl;
131
132fail:
133 kfree(ext_acl);
134 return ERR_PTR(-EINVAL);
135}
136
137/*
138 * Inode operation get_posix_acl().
139 *
140 * inode->i_mutex: don't care
141 */
142struct posix_acl *
143ext4_get_acl(struct inode *inode, int type)
144{
145 int name_index;
146 char *value = NULL;
147 struct posix_acl *acl;
148 int retval;
149
150 switch (type) {
151 case ACL_TYPE_ACCESS:
152 name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
153 break;
154 case ACL_TYPE_DEFAULT:
155 name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
156 break;
157 default:
158 BUG();
159 }
160 retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
161 if (retval > 0) {
162 value = kmalloc(retval, GFP_NOFS);
163 if (!value)
164 return ERR_PTR(-ENOMEM);
165 retval = ext4_xattr_get(inode, name_index, "", value, retval);
166 }
167 if (retval > 0)
168 acl = ext4_acl_from_disk(value, retval);
169 else if (retval == -ENODATA || retval == -ENOSYS)
170 acl = NULL;
171 else
172 acl = ERR_PTR(retval);
173 kfree(value);
174
175 if (!IS_ERR(acl))
176 set_cached_acl(inode, type, acl);
177
178 return acl;
179}
180
181/*
182 * Set the access or default ACL of an inode.
183 *
184 * inode->i_mutex: down unless called from ext4_new_inode
185 */
186static int
187__ext4_set_acl(handle_t *handle, struct inode *inode, int type,
188 struct posix_acl *acl)
189{
190 int name_index;
191 void *value = NULL;
192 size_t size = 0;
193 int error;
194
195 switch (type) {
196 case ACL_TYPE_ACCESS:
197 name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
198 if (acl) {
199 error = posix_acl_equiv_mode(acl, &inode->i_mode);
200 if (error < 0)
201 return error;
202 else {
203 inode->i_ctime = ext4_current_time(inode);
204 ext4_mark_inode_dirty(handle, inode);
205 if (error == 0)
206 acl = NULL;
207 }
208 }
209 break;
210
211 case ACL_TYPE_DEFAULT:
212 name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
213 if (!S_ISDIR(inode->i_mode))
214 return acl ? -EACCES : 0;
215 break;
216
217 default:
218 return -EINVAL;
219 }
220 if (acl) {
221 value = ext4_acl_to_disk(acl, &size);
222 if (IS_ERR(value))
223 return (int)PTR_ERR(value);
224 }
225
226 error = ext4_xattr_set_handle(handle, inode, name_index, "",
227 value, size, 0);
228
229 kfree(value);
230 if (!error)
231 set_cached_acl(inode, type, acl);
232
233 return error;
234}
235
236int
237ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
238{
239 handle_t *handle;
240 int error, retries = 0;
241
242retry:
243 handle = ext4_journal_start(inode, EXT4_HT_XATTR,
244 ext4_jbd2_credits_xattr(inode));
245 if (IS_ERR(handle))
246 return PTR_ERR(handle);
247
248 error = __ext4_set_acl(handle, inode, type, acl);
249 ext4_journal_stop(handle);
250 if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
251 goto retry;
252 return error;
253}
254
255/*
256 * Initialize the ACLs of a new inode. Called from ext4_new_inode.
257 *
258 * dir->i_mutex: down
259 * inode->i_mutex: up (access to inode is still exclusive)
260 */
261int
262ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
263{
264 struct posix_acl *default_acl, *acl;
265 int error;
266
267 error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
268 if (error)
269 return error;
270
271 if (default_acl) {
272 error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT,
273 default_acl);
274 posix_acl_release(default_acl);
275 }
276 if (acl) {
277 if (!error)
278 error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS,
279 acl);
280 posix_acl_release(acl);
281 }
282 return error;
283}
1/*
2 * linux/fs/ext4/acl.c
3 *
4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
5 */
6
7#include <linux/init.h>
8#include <linux/sched.h>
9#include <linux/slab.h>
10#include <linux/capability.h>
11#include <linux/fs.h>
12#include "ext4_jbd2.h"
13#include "ext4.h"
14#include "xattr.h"
15#include "acl.h"
16
17/*
18 * Convert from filesystem to in-memory representation.
19 */
20static struct posix_acl *
21ext4_acl_from_disk(const void *value, size_t size)
22{
23 const char *end = (char *)value + size;
24 int n, count;
25 struct posix_acl *acl;
26
27 if (!value)
28 return NULL;
29 if (size < sizeof(ext4_acl_header))
30 return ERR_PTR(-EINVAL);
31 if (((ext4_acl_header *)value)->a_version !=
32 cpu_to_le32(EXT4_ACL_VERSION))
33 return ERR_PTR(-EINVAL);
34 value = (char *)value + sizeof(ext4_acl_header);
35 count = ext4_acl_count(size);
36 if (count < 0)
37 return ERR_PTR(-EINVAL);
38 if (count == 0)
39 return NULL;
40 acl = posix_acl_alloc(count, GFP_NOFS);
41 if (!acl)
42 return ERR_PTR(-ENOMEM);
43 for (n = 0; n < count; n++) {
44 ext4_acl_entry *entry =
45 (ext4_acl_entry *)value;
46 if ((char *)value + sizeof(ext4_acl_entry_short) > end)
47 goto fail;
48 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
49 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
50
51 switch (acl->a_entries[n].e_tag) {
52 case ACL_USER_OBJ:
53 case ACL_GROUP_OBJ:
54 case ACL_MASK:
55 case ACL_OTHER:
56 value = (char *)value +
57 sizeof(ext4_acl_entry_short);
58 acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
59 break;
60
61 case ACL_USER:
62 case ACL_GROUP:
63 value = (char *)value + sizeof(ext4_acl_entry);
64 if ((char *)value > end)
65 goto fail;
66 acl->a_entries[n].e_id =
67 le32_to_cpu(entry->e_id);
68 break;
69
70 default:
71 goto fail;
72 }
73 }
74 if (value != end)
75 goto fail;
76 return acl;
77
78fail:
79 posix_acl_release(acl);
80 return ERR_PTR(-EINVAL);
81}
82
83/*
84 * Convert from in-memory to filesystem representation.
85 */
86static void *
87ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
88{
89 ext4_acl_header *ext_acl;
90 char *e;
91 size_t n;
92
93 *size = ext4_acl_size(acl->a_count);
94 ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
95 sizeof(ext4_acl_entry), GFP_NOFS);
96 if (!ext_acl)
97 return ERR_PTR(-ENOMEM);
98 ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
99 e = (char *)ext_acl + sizeof(ext4_acl_header);
100 for (n = 0; n < acl->a_count; n++) {
101 ext4_acl_entry *entry = (ext4_acl_entry *)e;
102 entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
103 entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
104 switch (acl->a_entries[n].e_tag) {
105 case ACL_USER:
106 case ACL_GROUP:
107 entry->e_id = cpu_to_le32(acl->a_entries[n].e_id);
108 e += sizeof(ext4_acl_entry);
109 break;
110
111 case ACL_USER_OBJ:
112 case ACL_GROUP_OBJ:
113 case ACL_MASK:
114 case ACL_OTHER:
115 e += sizeof(ext4_acl_entry_short);
116 break;
117
118 default:
119 goto fail;
120 }
121 }
122 return (char *)ext_acl;
123
124fail:
125 kfree(ext_acl);
126 return ERR_PTR(-EINVAL);
127}
128
129/*
130 * Inode operation get_posix_acl().
131 *
132 * inode->i_mutex: don't care
133 */
134struct posix_acl *
135ext4_get_acl(struct inode *inode, int type)
136{
137 int name_index;
138 char *value = NULL;
139 struct posix_acl *acl;
140 int retval;
141
142 if (!test_opt(inode->i_sb, POSIX_ACL))
143 return NULL;
144
145 acl = get_cached_acl(inode, type);
146 if (acl != ACL_NOT_CACHED)
147 return acl;
148
149 switch (type) {
150 case ACL_TYPE_ACCESS:
151 name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
152 break;
153 case ACL_TYPE_DEFAULT:
154 name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
155 break;
156 default:
157 BUG();
158 }
159 retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
160 if (retval > 0) {
161 value = kmalloc(retval, GFP_NOFS);
162 if (!value)
163 return ERR_PTR(-ENOMEM);
164 retval = ext4_xattr_get(inode, name_index, "", value, retval);
165 }
166 if (retval > 0)
167 acl = ext4_acl_from_disk(value, retval);
168 else if (retval == -ENODATA || retval == -ENOSYS)
169 acl = NULL;
170 else
171 acl = ERR_PTR(retval);
172 kfree(value);
173
174 if (!IS_ERR(acl))
175 set_cached_acl(inode, type, acl);
176
177 return acl;
178}
179
180/*
181 * Set the access or default ACL of an inode.
182 *
183 * inode->i_mutex: down unless called from ext4_new_inode
184 */
185static int
186ext4_set_acl(handle_t *handle, struct inode *inode, int type,
187 struct posix_acl *acl)
188{
189 int name_index;
190 void *value = NULL;
191 size_t size = 0;
192 int error;
193
194 if (S_ISLNK(inode->i_mode))
195 return -EOPNOTSUPP;
196
197 switch (type) {
198 case ACL_TYPE_ACCESS:
199 name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
200 if (acl) {
201 error = posix_acl_equiv_mode(acl, &inode->i_mode);
202 if (error < 0)
203 return error;
204 else {
205 inode->i_ctime = ext4_current_time(inode);
206 ext4_mark_inode_dirty(handle, inode);
207 if (error == 0)
208 acl = NULL;
209 }
210 }
211 break;
212
213 case ACL_TYPE_DEFAULT:
214 name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
215 if (!S_ISDIR(inode->i_mode))
216 return acl ? -EACCES : 0;
217 break;
218
219 default:
220 return -EINVAL;
221 }
222 if (acl) {
223 value = ext4_acl_to_disk(acl, &size);
224 if (IS_ERR(value))
225 return (int)PTR_ERR(value);
226 }
227
228 error = ext4_xattr_set_handle(handle, inode, name_index, "",
229 value, size, 0);
230
231 kfree(value);
232 if (!error)
233 set_cached_acl(inode, type, acl);
234
235 return error;
236}
237
238/*
239 * Initialize the ACLs of a new inode. Called from ext4_new_inode.
240 *
241 * dir->i_mutex: down
242 * inode->i_mutex: up (access to inode is still exclusive)
243 */
244int
245ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
246{
247 struct posix_acl *acl = NULL;
248 int error = 0;
249
250 if (!S_ISLNK(inode->i_mode)) {
251 if (test_opt(dir->i_sb, POSIX_ACL)) {
252 acl = ext4_get_acl(dir, ACL_TYPE_DEFAULT);
253 if (IS_ERR(acl))
254 return PTR_ERR(acl);
255 }
256 if (!acl)
257 inode->i_mode &= ~current_umask();
258 }
259 if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
260 if (S_ISDIR(inode->i_mode)) {
261 error = ext4_set_acl(handle, inode,
262 ACL_TYPE_DEFAULT, acl);
263 if (error)
264 goto cleanup;
265 }
266 error = posix_acl_create(&acl, GFP_NOFS, &inode->i_mode);
267 if (error < 0)
268 return error;
269
270 if (error > 0) {
271 /* This is an extended ACL */
272 error = ext4_set_acl(handle, inode, ACL_TYPE_ACCESS, acl);
273 }
274 }
275cleanup:
276 posix_acl_release(acl);
277 return error;
278}
279
280/*
281 * Does chmod for an inode that may have an Access Control List. The
282 * inode->i_mode field must be updated to the desired value by the caller
283 * before calling this function.
284 * Returns 0 on success, or a negative error number.
285 *
286 * We change the ACL rather than storing some ACL entries in the file
287 * mode permission bits (which would be more efficient), because that
288 * would break once additional permissions (like ACL_APPEND, ACL_DELETE
289 * for directories) are added. There are no more bits available in the
290 * file mode.
291 *
292 * inode->i_mutex: down
293 */
294int
295ext4_acl_chmod(struct inode *inode)
296{
297 struct posix_acl *acl;
298 handle_t *handle;
299 int retries = 0;
300 int error;
301
302
303 if (S_ISLNK(inode->i_mode))
304 return -EOPNOTSUPP;
305 if (!test_opt(inode->i_sb, POSIX_ACL))
306 return 0;
307 acl = ext4_get_acl(inode, ACL_TYPE_ACCESS);
308 if (IS_ERR(acl) || !acl)
309 return PTR_ERR(acl);
310 error = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
311 if (error)
312 return error;
313retry:
314 handle = ext4_journal_start(inode,
315 EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
316 if (IS_ERR(handle)) {
317 error = PTR_ERR(handle);
318 ext4_std_error(inode->i_sb, error);
319 goto out;
320 }
321 error = ext4_set_acl(handle, inode, ACL_TYPE_ACCESS, acl);
322 ext4_journal_stop(handle);
323 if (error == -ENOSPC &&
324 ext4_should_retry_alloc(inode->i_sb, &retries))
325 goto retry;
326out:
327 posix_acl_release(acl);
328 return error;
329}
330
331/*
332 * Extended attribute handlers
333 */
334static size_t
335ext4_xattr_list_acl_access(struct dentry *dentry, char *list, size_t list_len,
336 const char *name, size_t name_len, int type)
337{
338 const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
339
340 if (!test_opt(dentry->d_sb, POSIX_ACL))
341 return 0;
342 if (list && size <= list_len)
343 memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
344 return size;
345}
346
347static size_t
348ext4_xattr_list_acl_default(struct dentry *dentry, char *list, size_t list_len,
349 const char *name, size_t name_len, int type)
350{
351 const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
352
353 if (!test_opt(dentry->d_sb, POSIX_ACL))
354 return 0;
355 if (list && size <= list_len)
356 memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
357 return size;
358}
359
360static int
361ext4_xattr_get_acl(struct dentry *dentry, const char *name, void *buffer,
362 size_t size, int type)
363{
364 struct posix_acl *acl;
365 int error;
366
367 if (strcmp(name, "") != 0)
368 return -EINVAL;
369 if (!test_opt(dentry->d_sb, POSIX_ACL))
370 return -EOPNOTSUPP;
371
372 acl = ext4_get_acl(dentry->d_inode, type);
373 if (IS_ERR(acl))
374 return PTR_ERR(acl);
375 if (acl == NULL)
376 return -ENODATA;
377 error = posix_acl_to_xattr(acl, buffer, size);
378 posix_acl_release(acl);
379
380 return error;
381}
382
383static int
384ext4_xattr_set_acl(struct dentry *dentry, const char *name, const void *value,
385 size_t size, int flags, int type)
386{
387 struct inode *inode = dentry->d_inode;
388 handle_t *handle;
389 struct posix_acl *acl;
390 int error, retries = 0;
391
392 if (strcmp(name, "") != 0)
393 return -EINVAL;
394 if (!test_opt(inode->i_sb, POSIX_ACL))
395 return -EOPNOTSUPP;
396 if (!inode_owner_or_capable(inode))
397 return -EPERM;
398
399 if (value) {
400 acl = posix_acl_from_xattr(value, size);
401 if (IS_ERR(acl))
402 return PTR_ERR(acl);
403 else if (acl) {
404 error = posix_acl_valid(acl);
405 if (error)
406 goto release_and_out;
407 }
408 } else
409 acl = NULL;
410
411retry:
412 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
413 if (IS_ERR(handle))
414 return PTR_ERR(handle);
415 error = ext4_set_acl(handle, inode, type, acl);
416 ext4_journal_stop(handle);
417 if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
418 goto retry;
419
420release_and_out:
421 posix_acl_release(acl);
422 return error;
423}
424
425const struct xattr_handler ext4_xattr_acl_access_handler = {
426 .prefix = POSIX_ACL_XATTR_ACCESS,
427 .flags = ACL_TYPE_ACCESS,
428 .list = ext4_xattr_list_acl_access,
429 .get = ext4_xattr_get_acl,
430 .set = ext4_xattr_set_acl,
431};
432
433const struct xattr_handler ext4_xattr_acl_default_handler = {
434 .prefix = POSIX_ACL_XATTR_DEFAULT,
435 .flags = ACL_TYPE_DEFAULT,
436 .list = ext4_xattr_list_acl_default,
437 .get = ext4_xattr_get_acl,
438 .set = ext4_xattr_set_acl,
439};